<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>

<script>
    // 唯一全局变量
    let chenApp = {};

    // 定义全局变量
    chenApp.name = "Application";
    chenApp.add = function (a, b) {
        return a + b;
    };
</script>

</body>
</html>